Thermal conductivity of overdoped BaFe1.73Co0.27As2 single crystal: Evidence for nodeless multiple superconducting gaps and interband interactions
Thermal conductivity of overdoped BaFe1.73Co0.27As2 single crystal: Evidence for nodeless multiple superconducting gaps and interband interactions
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过掺杂 BaFe1.73Co0.27As2 单晶的热导率：无节点多重超导间隙和带间相互作用的证据
DOI：
10.1103/physrevb.81.094520
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发表时间：
2009-08
影响因子：
3.7
通讯作者：
Li, S. Y.
中科院分区：
文献类型：
--
作者：
Dong, J. K.;Zhou, S. Y.;Guan, T. Y.;Qiu, X.;Zhang, C.;Cheng, P.;Fang, L.;Wen, H. H.;Li, S. Y.
测量了过掺杂FeAs基超导体BaFe_（1.73）Co_（0.27）As_2（Tc = 8.1K）单晶的面内热导率K_（appa），其值可达80 mK。在零磁场下，剩余的线性项kappa（0）/T可以忽略不计，表明在ab平面上存在一个无节点的超导能隙。在磁场中，kappa（0）/T迅速增大，与传统的s波超导体有很大不同。这种反常的kappa（0）/T（H）关系可能揭示了过掺杂BaFe 1.73Co 0.27As 2中奇异的超导能隙结构：消失空穴（β）口袋的能隙比包含大部分载流子的电子（γ和δ）口袋的能隙大得多。这种奇异的带隙结构是由带间相互作用诱导的超导态的证据，其中态密度较小的带具有较大的带隙。
The in-plane thermal conductivity kappa of overdoped FeAs-based superconductor BaFe1.73Co0.27As2 (T-c=8.1 K) single crystal was measured down to 80 mK. In zero field, the residual linear term kappa(0)/T is negligible, suggesting a nodeless superconducting gap in the ab plane. In magnetic field, kappa(0)/T increases rapidly, very different from that of conventional s-wave superconductors. This anomalous kappa(0)/T(H) may reveal an exotic superconducting gap structure in overdoped BaFe1.73Co0.27As2: the vanishing hole (beta) pocket has a much larger gap than the electron (gamma and delta) pockets which contain most of the carriers. Such an exotic gap structure is an evidence for superconducting state induced by interband interactions, in which the band with the smaller density of states has a larger gap.